Flotation machines often include a tank that retains a slurry, or pulp. Examples of such machines may be appreciated from U.S. Pat. Nos. 4,425,232, 4,800,017, and 5,205,926. The entirety of U.S. Pat. Nos. 4,425,232, 4,800,017, and 5,205,926 are incorporated by reference herein. The slurry retained by such tanks may include solid material such as ore or minerals that is mixed in a liquid such as water. For example, the material present in the slurry may include particles of copper bearing minerals, coal, iron minerals, phosphate rock, potash, silica, base metal sulfide or precious metal.
The slurry retained in the tank may be aerated to generate froth to suspend solid particles in the froth. The froth may be a large amount of bubbles formed at the top of the slurry in the tank. For instance, froth may be generated via a forced air technology to create bubbles and generate the froth. Alternatively, bubbles may be generated via a self-aspirated technology to create the froth. The tanks are designed so that the froth, which contains the solid particles, may be passed into one or more launders adjacent to the tank to separate the valuable minerals from the other liquid and other material. It should be understood that after the material is sent to the one or more launders, it may be further processed to recover the desired material.
Rotors may be included in each flotation cell of a flotation machine to agitate the slurry for purposes of forming air bubbles that capture particles and rise to the top of the slurry to form froth. Air may be forced through the rotor and expelled out adjacent blades located at the bottom of the rotor that is rotated so that air is mixed with the slurry to generate bubbles for forming the froth above the slurry retained in the tank. Such a froth so generated, however, may be difficult to maintain unless the rotor is rotated at relatively fast speed and may also require a rotor to be relatively large. Such size and speed constraints increase the cost of fabricating such flotation machines and operating such machines.
Further, such rotors typically include blades that generate a velocity spike in an exit stream of slurry that consumes a relatively significant amount of power used to rotate the rotor but fails to provide any meaningful improvement to froth formation performance. This design feature also increases the costs associated with operating the flotation machines.
A new rotor design is needed for flotation cells of flotation machines. The new rotor design preferably reduces the cost of manufacturing rotors and reduces the operating costs associated with moving of the rotors during operation of the flotation cells. Preferably, such a rotor design also improves the bubble generation performance of the rotors as compared to conventional rotors.